Intermittent-tension stitch-forming mechanism



June 8 1926.

c. w. MUELLER INTERMI'ITENT TENSION STITCH FORMING MECHANISM.

Filed Feb. 14, 1924 8 Sheets-Sheet 1 anon 119$ 'llarZe-s itlfzzell rJune 8 1926.

' 1,588,134 C. W. MUELLER INTERMITTENT TENSION STITCH FORMING MECHANISMFiled Feb. 14. 1924 8 s s 2 attozwuq June 8 1926.

c. w; MUELLER INTERMITTENT TENSION STITCH FORMING MECHANISM 8Sheets-Sheet 5 Filed Feb. 14, 1924 arm m1:

June 8 1926; I

C. W. MUELLER INTERMITTENT TENSION STITCH FORMING MECHANISM Filed Feb.14, s Sheets-Sheet 4 attoz may;

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c. w. MUELLER INTERMITTENT TENSION STITCH FORMING MECHANISM Filed Feb.14, 1924 8 Sheets-Sheet 5 Jung s, 1926, 1,588,134

c. w. MUELLER INTERMITTENT TENSION STITCH FORMING MECHANISM Filed Feb.14, 1924 8 sh ts-sheet, e

Jr Y .95" .900? j gmnnio'c .99 .97 97 fiarlesflZJ/aella;

June 8 1926. 1,588,134

C. W. MUELLER INTERMI [TTENT TENSION STITCH FORMING MECHANISM Filed Feb.14. 1924 8 Sheets-Sheet '7 mw a 3% C. W. MUELLER INTERMITTENT TENSIONSTITCH FORMING MECHANISM June 8 1926.

Filed Feb. 14, 2 8 Sheets-Sheet 8 I zjwvzntoz ma W/Vueller Patented June8, 1926.

UNITED STATES PATENT OFFICE.

CHARLES W. MUELLER, O1 ST. LOUIS, MISSOUIEI, ASSIGNOB '10LEWISINVISIIBLI STITCH MACHINE 00., OF ST. LOUIS, MISSOURI, ACORPORATION OF INTEBMI'ITENT-TENSION STITCH-FORMING MECHANISM.

Application filed February 14,1924. Serial No. 692,696.

' This invention relates to new and useful improvements in sewingmachines enerally, although more particularly to t e stitch forminmechanism of blind stitch machines.

In bhnd stitch operations, particularly for joining a base layer and asuperimposed- The principal object of my invention is to provide in ablind stitch sewing machine for joining a base. layer and a superimposedlayer, an automatic intermittent tensioning mechanism for the thread orthreads where-. by certain of the stitches which penetrate thesuperimposed layer will be set under a ti ht tension, while theremaining stitches which penetrate the superimposed layer and enterandemerge from the same face of-the base layer will be set under a loosetension, thus creating a sufficiently tight seam to meet practicalrequirements, and at the same time preventing the 'ap arance of dimplesor uckering on the fairrside of Y the base ayer. Another object of theinvention is to provide an intermittent plunger mechanism wherein theplan er at predetermined intervals elevates the base layer. into thepath of reciprocation of the needle so as to insure certain of thestitches being made to penetrate the superimposed layer and enterandemergefrom the same face of the base layer, and an intermittent threadtension release mechanism, which is so timedas to permit the thread orthreads ofthe stitches thus being formed to be loosely concatenated.

A furtherobjectof my invention resides in the needle thread tensioningmeans whereby the thread when released will still be under suflicienttension to avoid the thread being pulled from the supply when theneeture of the invention is better for general practical requirements.

With the above and Ollllel objects in view which will more readilyappear as the naunderstood,

combination and arrangement of parts hereinafter more fully described,illustrated and claimed; 7

In the accompanying drawin which illustrate one embodiment of myinvention, 4 I

Figure I is a perspective view of the stitching headshowing theapplication of my intermittent tension releasing mechanism.

Figure 2 is an end elevation of a machine embodying my invention. I

Figure 3 is a detail vertical longitudinal sectional view showing thedriving mechanism of the machine.

Figure 4 is a detail vertical transverse sectional view taken on theline 44 of Fig. 3.

Figure 5 is a top plan view of the stitching head.

Figure 6 is a detail horizontal sectional view showing the intermittenttension releasin mechanism.

, igure 7 is an enlarged detail elevation of the releasing mechanism,showing the inter changeable actuating cams.

Figure 8 is a perspectlve view showing thesame consists in the novelconstruction,

the various (parts of the releasing mechanism in separate relation.

Figure 9 is an enlarged plan view of the seam produced by my invention.

' Figure 10 is a sectlonal view of the, seam taken on the line 1010 ofFig. 9.

Figure 1-1 is a sectional view of the seam.

taken on the line 1111 of Fi 9. Figure 12 is a detail verticalongitudinal sectional view showing the plunger and its actuating means,the feed' dog, -and thework .clamp.

Figure 13 is'a plan view of the presser foot showing the application ofthe fabric.

Figure 14 is an enlarged view, more or less diagrammatic, showingtherelative positions of the plunger, the fabric, and the needle when t esuperimposed layer only is being stitched.

Figure 15 is a similar view. but showing the relation of the parts whenthe superimosed layeris being stitched to the base ayer. v 1

ool

Figure 16 is a plan of the foot. Figure 17 is a perspective view of thecradle. 1

Figure 18 is a longitudinal sectional view of the base showing the meansfor supporting and depressing the work. presenting mechanism.

Figure 19 is a diagrammatic view showing the'low position ofreciprocation of the plunger, and Figure is a similar view but showingthe high position of reciprocation of the plun er. Li e referencenumerals designate corresponding parts in all the figures of thedrawlngs.

The sewing machine frame consists of a' base 5 having at one end "thework handling is a link 20. The me I mechanism, a post 6 which extendsupwardly from the other end thereof and an overhanging arm 7 which issupported by the post and carries at its outer or free end a stitchinghead 8, said stitching head being disosed above the work handlingmechanism.

e stitching head carries at its lower extremity a presser foot 9 forcooperation with the stitch forming and work handling mechanisms.

The operating parts carried b the stitching head Sand the work handingmechanism carried by the base 5 are driven from a main shaft 10 whichextends longitudinally in the overhanging arm 7 and is suitablyjournaled therein, said shaft having a hand wheel Pulley 11 fixed to theright hand end thereo The work handling mechanism which cooperates withthe presser foot 9 includes a feed dog 12 and a work clamp 13. The feeddog is of the Jr-motion t pe, that is, it has a backward and forwarmovement and an' up and downmovement. vThe backward and,

forward movement of. the" feed dog is obtained through a rock shaft 14which I term the feed travel shaft and the up and down movement of thefeed dog is btained from a rock shaft 15 which I term t e feed liftshaft. These rock shafts 14"and 15 extend longitudinally within the base5 and have their right hand ends journaled in bearings formed in adepending lug 16 and their left hand ends journaled 1n bearings formedin a block 17 detachably secured to the left hand end of the base 5 byscrews 18--18. Fixed to the outer end of the feed travel shaft 14 is arock arm 19 and pivotally connecting the outer end of the rock arm andthe forward extremit of the feed dog 12 arm 19 extends in a generalvertical direction and the link 20 extends in a general horizontaldirection, thus upon movement of, the rock arm the link 20 will impartbackward'and forward movementsjto the feed dog 12. The feed dog 12 ispivotally connected as at 21 tothe upper end of a substantiallyvertically dis-l I posed link 22, the lower end of saidlink beingpivotally connected as at 23 to the horizontal arm 24 of a bell cranklever 25, the- 30. fixed to the feed lift? shaft 15. In order tomaintain the feed surface of the feed dog in a substantially horizontalplane during the feeding movements thereof, I provide a spring 31 whichis connected between a 32 on the link 22 and a endent tail 33 fixed tothe feed dog. It w1ll,-therefore, be ob-' served that. upon rockingmovement of the shaft-1 5 the vertical link 22 will'be bodily raised andlowered and consequently the- \feed dog will be given its up and downmovements. By proper timing of the shafts 14 and 15 a 4-wa f eed motionwill'be imparted to the fee dog.

g The bell crank lever 25 is pivoted as at 34, I andthls pivot is fixedto ahead 35 securedto the lower end of a guide post 36, said headandpost forming a'vertically movable carrier. The post 36 is mounted forvertical sliding movements in a bore formed in the block 17, and thisblock is formed with a seat 37 for receiving and limiting the upwardmovement of the carrier. 1 This car-- rier is normally held in itshighest position by means of a fiat spring 38 the inner end of which isrigidly secured to the base 5 and the free end thereof is disposed underthe carrier so as to yieldably hold the latter in its highest position.The upper end of the post projects above the block 17 and carries a airof rearwardly extending arms 39-39 tween which is pivoted as at'40 thework clamp 13. From the foregoing, it will be observed that when thecarrier is moved downwardly against the tension of the spring 38, boththe feed dog 12 and the work clamp 13 will be correspondingly moved,thus permitting the work presenting mechanism to be depressed as anentirety. In order to so depress the work presenting mechanism, I have:provided an operating lever 41 which is fulcrumed on the base 5 and hasone end disposed in contact with the upper face of the head 35., Theother end of the lever is adapted to be raised through the a plicationof a knee shiftingv device or trea le,-neither of which however is shownin the "drawings. i

7 From the foregoing, it will be observed that when the feed dog ,iselevated to its highest position, the fulcrum .of the bell crank lever25 is then shifted to the pivot 23 and consequently the last part of therocking movement of the crank arm 30 will cause the bell crank 25 to bemoved dowm wardly about its fulcrum 23 thus lowering the work clamp 13.The parts are so timed that the work clamp is thus lowered prior to thefeeding movement of the feed dog. The reverse order of movement willtakeplace at substantially the time when the feed dog reaches the end of itsfeeding stroke, thus causing the clamp to engage the fabric and clampthe latter against the foot prior to the time the feeddog begins itsdownward movement. f

In order to rock the feed travel shaft 14 and the feed lift shaft 15 Iprovide the main shaft 10 with eccentrics 42 and 43 respectively. Aconnection rod 44 has its upper end engageable with the eccentric 42 andits lower end pivotally connected asat. 45

to a rock arm 46 fixed tothe rock shaft 14.

A connection rod 47 has its upper end engageable with the eccentric 43and its lower end pivotally connected as at 48 to a rock arm 49 fixed tothe shaft 15. It will be noted thatthe connection rods 44 and 47 aredisposed within the post 6 of the machine frame.

The fabric as it is fed past the stitching head is adapted to beintermittently crimped or bent so as to form a node .Which will bepositioned in the path. of the needle whereby the latter will, or willnot, depending upon the height of the node, enter said node and projecta penetrant needle thread loop therethrough. as will hereinafter be morefully described. In' order to provide for this crimping or bendingaction of the material the presser foot 9 is formed with an opening 50..The material is upwardly bent or crimped into this opening by means "ofa reciprocatory plunger 51 which extends upwar'dly through the feed dog12 and work clamp 13. This plunger is mounted for vertical slidingmovements within a barrel 52 fitted within a bore 53 formed in the endblock 17. The lower end of the plunger 51 is formed with a reduced end54 forming a resultant shoulder 55. The lower end of the barrel 52 isfixed to 9. lug 56and the .reduced end 54 of the plunger extends throughan opening 57 formed in 'said lug and threaded onto the lower projectingend thereofv are lock nuts 58. Disposed within the barrel 52 between theshoulder of the plunger and the lug'56 is a coil spring 59 whlchyieldably holds the plunger in its highest position relative to the lug56. It will be evident that when the barrel is moved upwardly theplunger will be moved therewith, but just as soon as the plunger engagesthe fabric a resistance to the upward movement of said plunger will takeplace and the spring 59 'will permit the barrel to continue its movementwhile the plunger spring 59 is being compressed.

The plunger 51 is vertically reciprocated through the medium of a rockshaft 60 which extends longitudinally of the base 5.

speed of rotation of the cam roller shaft 70 The rock shaft 60 isprovided with a crank arm 61 which is connected by a link 62 to the lug56; The rock shaft 60 is located beg low the plunger and the link 62extends substantially vertically .when the plunger is at its highestposition. I I

For the purpose of bodily varyingthe vertical position of, reciprocationof the plunger, I have supported the rock' shaft 60 for vertical bodilymovements and to this end I have journaled the shaft in bearings formedin a cradle or rocking frame which I have designated as a .whole bythereference numeral 63. This cradle includes 'a rock shaft 64 havingone end supported for rocking movements on a pin 65 carried by the endwall of the base 5 and its other end: journaled in the depending lug 16of said base. The rock shaft 64 is provided with sleeve 69 is a face cam72 and this cam is formed on its upper face with a curved surfacecontaining diametrically opposed high points 7 3-73 and diametricallyopposed low tends upwardly through the post 6 of the frame and is drivenfrom the main shaft 10 by a gear coupling 75 which reduces the relativeto the main shaft 10 by the ratio 1 to '4. This gear coupling 75includes a spiral gear 75 which is fixed to the cam roller shaft throughthe medium of a collar and a spiral gear 75 which is fixed to the mainshaft 10. The cam roller shaft extends through a concentric opening inthe cam 7 2 and fixed to the shaft directly above the cam face of saidcam is a sleeve 76 which carries a cam roller 77 engageable with the camface of the cam. The upper end of the cam roller shaft.70 above the gearcoupling 75 is mounted within a sleeve 78 which has threaded, engagement3 with an opening formedin a plate 79 which is detachably points 74-74.The cam roller shaft 70 exsecured to the upper end of the frame. The

lower end of the sleeve rests on the collar 7 5 of the gear coupling.Fixed" to the upper end of the sleeve 78 is a knurled head 80 by meansof which the vertical position of the sleeve may be adjusted. A screw 81is threaded into the upper end ofthe cam roller shaft 70 and the head ofthis screw bears against the upper end of the sleeve 78 and therebyretains the cam roller shaft 70 er 77, thus elevating the plunger shaft60,

eeve 78. 'In other words, the collar 75 prevents upward movement" of thecam'roller shaft 70 relative to thesleeve '78, and the screw 81 preventsdownward movement of the cam roller: shaft relative to said sleeve. Thusupon vertical movement of the sleeve 7 i 78, the cam roller shaft 70will be correspondingly moved. Downwardmovement of the cam rollershaft.7O causes the cradle 63 to be rocked through the medium of therollthe latter being'moved upwardly in an are .about the pivot of thecradle. The upward bodily movement of the shaft.60 will in turn bodilyelevate the position of reciprocation of the plunger through the mediumof the rock arm 61, link 62 and lug 56, as diagrammatically shown inFigure 20. Upward adjustment of the cam roller shaft 70 will lower theposition of the shaft 60 as diagrammatically shown in Figure 19.

The plunger shaft 60 is rocked in the sup porting cradle or frame 63 bytherock arm 49, the outer end of which is pivotally connected as at 49to the upper end of a substantially vertically disposed link 49, thelower end of the link being pivotally connected as at 49 to a rock arm60 fixed to the plunger shaft 60. Inasmuch as the cam 72 is' providedwith two high points and two low points, and the main shaft makes fourcomplete revolutions to one of the 0am roller shaft 70, it follows thatthe bodily ppsition of reciprocation of the plunger will elevated.durlng every other revolution of the main shaft, and that the plungerwill be reciprocated when the plunger rock shaft 60 l is in its highposition and also when it is in its low position.v

The plate 79 IS'SlOttBd to form a clamp for the sleeve 78, and a screw 79 cooperates with the clamp to lock the sleeve against turning.

' In order to turn the sleeve it is necessary to first release theclamp. The proper bodily position of reciprocation of the plunger maythen be obtained by actuating the sleeve 78 after which the sleeve isclamped against.

further freerotation by'the screw 79, thus permanently fixing or settingthe bodily position ofreciprocation of the plunger.

In order to control the depth of needle penetration in the superimposedfabric, I have provided a coil sprng 82.which is disposed between thefront walliof the base. 5 of the frame and a rock arm 83 fixed to thecradle 63. The rock arm 83 is formed with a rectangular slot 84 and disosed in this a slot is an angular sleeve 85 havmga threadbolt 87 passes.

' against downwardmovement"relative to the; the front wall. The rear endof the angular numeral 90 and includes a base layer 91 and asuperimposed layer 92, the latter being in this case anintegral part ofthe base layer and forming a-hem or fell. The marginal edge portion ofthesuperimposed layer 92 is provided with a binding 93 and this bindinis secured to the superimposed layer by a ine of through-and-throughstitches 94.

- The superimposed layer 92 is secured to the In' these drawbase layer.91 by'a line of stitches .allof which penetrate the superimposed layer.At intervals, preferabl regular intervals,for regular s acing t ereof,"certain of the stitches w ich' penetrate the superimposed the u perfacebf the base layer 91. The stitches w Ichlayer 92 also pass into andout o penetratethe superimposed layer only are tightly set whereas-thosestitches which also pass into and out'of the upper face of the ase layerare loosely set. As a result, a

sufficiently tight seam for all ractical purposes is created and theformation of dimples i or puckers on the under or fair side of thebase'layer will be prevented. These stitches are preferably formedthrough the instrumentallties of aneedle 95 and a',co--

shown operating book 96', the latter bein in Fi 1 of the drawings. Thenee 1e 95 is curve and oscillates about a horizontal axis disposeddirectly above the of the needle in the fabric.

int of entrance. he needle oscillates in a vertical plane disposed at anan 10 to the general lineof the seam andin t is instance I have "shownthe needle as being disposed at an angle of 45. The needle enters thesuperimposed layer 92 'at a point.

adjacent theline of stitches 94 and under the marginal edge of thebinding which is,

said stitches. '94; The needle secured by thread 96 is formed into. "aser1es of loose penetrant loops 97 and also mto a series oftightpenetrant loops 98, the latter being 9.1- m o I ternately disposedwith respect to the loops 97. The loops 97 pass through the superimposedlayer92 and thence into and out of the upper face of the base'layer 9 1,and

the bite of each loopro'ects above the face of said base layer. T e.oops 98 do not pass into the base layer 91- but referably terminatebetween the upper an lower faces of the superimposed la er 92,. Theseloops are.

keyed, thatis locke by a bobbin thread 99. The specific seam abovedescribed forms the clamp means;

subject matter of my copending application Ser. 190,685,174 filedJanuary 9, 1924.

' The presser foot 9 is rigidly but detachably secured to the head 8 bymeans of screws 100-100. This foot is, of course, disposed directlyabove the feed dog 12 and the work 13 and the foot is formed with theopemn to receive the node of fabric forme by the plunger 51. Thehorizontal axis of the needle is disposed directl above and in alignmentwith the lon itud1- nal axis of the plunger 51. The opemng 50 is a artof a centrally disposed and rearwardl y extending fabric guiding slot102, which extends in theline of feed to a point beyond the plunger51,.the rear or inner end of the guiding slot 102 terminating in rear ofthe lunger 51 in an offset portion 103. A needle guide 104 which isformed of hardened steel is detachably secured to the foot by a screw105 and this guide is formed with a guiding recess 106 for the needle95. This guide is attached to that portion of the foot on the right-handside of the fabric guiding slot 102 and one end thereof terminates ina.combined edge guide and lifting device 107. This combined edge guideand lifting device 107 is employed .for the purpose of engaging themargin of the bindin 103 and elevating the marginal edge thereo abovethe path of the needle whereby the latter "may penetrate thesuperimposed layer92 at a point close; to the line ofthrough-a'nd-throngh stitches 94, thus permittin the marginal edgeportion of the 7 body to utimately cover or conceal the con- 108 is ashelf 109 w the marginal. edge V cation of the yoke shaped needle bar110 tion is pivoted to the lower end of necting 'needlethread 96.Secured to the left hand side of the Er'esser foot by a screw ich servesto support portion of the'superimposed layer 92 above the path of theneedle thereby preventing'the needle from "penetrating the superimposedlayer except at the original point of entrance, viz: ad'acent themarginal edge of the binfiidg. 'I he shelf 109 furthermore supports the.superimposed layer-92 above the path of reciprodoes not at any timeengagesaid superimposed layer 92. I i

The needle 95 is centrally carried by a pivoted as at 111 at ,theextremities of its limbs on the head 8. One of the needle bar limbs hasa lever prolongation and this lever prolongaa link 112 with a wrist pin113 of a counterwei hted crank arm7114 carried by a jack sha 115 whichis jonrnaled in the head 8 and is operated from the' mainfshaft 10 by a1-to-1 ear coupling 115'. The axis of the needle ar is disposed at anangle of 45 relative to the line of feed and consequently the nee tightvand loose plunger 51 so that said plunger than the spring much as Iemploy a 1-to-1 gear couplin 115",

' the needle will make one complete osci ation to every rotation of themain shaft 10. The

needle cooperates with the hook 96 to form a series of lock stitches.This hook is mounted on the shaft 116 and'this shaft is driven. in a2-to-1 relation relative to the .rotation of the jack shaft 115 throughthe medium of beveled gears 117, vertical shaft 118 and spiral gearcoupling 119, the gears of which coupling are res ectivel carried by the'ack shaft 115 and t e'vertical shaft 118. Thus the hook will be rotatedtwice for each oscillation of the needle and will cooperate with theneedle in a manner well known to those skilled in this art.

' A take-up arm 120 for the needle thread is fixed to a sleeve or hub-121 which is jonr naled on a horizontal pin $122 in the head 8.

A rock arm 123 is also fixed to the sleeve or B5 hub 121 and has slidingengagement with a blocli124 which is' pivotally connected as at 125 to alaterally extending rigid arm 126 of the link 112. The take-up arm 120is thus given a differential rate of motion in an appropriately timedrelation to the needle oscillations. In the cyclic operation, thetake-up lever is given a rapid rise, a slow descent and an extendeddwell in its lowered position.

The needle thread 96 is led from the supply to a stationary thread guide127 fixed to the head 8, thence through tension disks 128'and 129respectively of anintermittent tension device, through a stationaryguide 130,

thence through the spring tension 131,

thence throng a'guide 132 formed in the end of the take-up arm 120 andthence to the needle 95.

The intermittent tension device acts on the needle thread 96 so as toform alternatestitches as'hereinbefore ascribed. The tension disks 128and 129 i are mounted on a horizontal rod 133 mounted to slidelongitudinally in a bore 134' formed in the head 8. This rod ispreferably held against rotary by, a screw 135 having threadedengagementwith the head 8 and operating in a longitudinal egroove 136 formed insaid rod. Form 128 and 129 are disposed between the frame 8,and saidflange 137. The front end ofthe rod is threaded and is provided withanut Between the disk 129 and the nut 138 is a light coil 8 ring 139.The. rod 133 extends rearwa formed with a threaded end portion 140 havlna nut .141 threaded therwn. Interposed tween the frame 8 and the nut 141is a heavy .co1l spr1'ng142 which has considerably more tensionalstrength or pressure 139; The spring 142 urges the rod 143 rearwardlyand causes the flange onthe front end of the rod 133 is a flange orshoulder 137 and the two disks movement, however,

y of the frame 8' and is or shoulder 137 to force the disks against eachother and against the frame 8. Thus in'. the normal position of thevparts, the needle thread is under the heavy tension of the spr' 142,and the light spring 139 has ractlca y no effect on the thread; The rod33 is ada ted to be moved forwardly so as to relieve t e disksof theheavy pressure exagainst said disks and needle t erted by the spring142, but permits the spring 139 to still exert its light tension readpass ing therebetween. In order to intermittentlyactuate therod 133andthereby intermitshaft 144 is such that the high point 147 will tapactuate the tension rod 133 durin alternateoscillations of the needle.Imme iatel following the casting. off of the needle t ead loop from thepoint of the hook 96- the takeuparm120 begins its upward movement forthe purpose of taking up slack in said needle thread and thereb settingthe stitch. In view-of the fact t at the cam 147 actuates the tensionrelease during the settin of every other stitch, it follows that the aterpate stitcheswill be loosely and tightly set.

Occasionally it may be desired to form a seam in which all ofthestitches are looselyv set. To this end I have providedthe shaft 144 witha surface cam 148 which is disposed adjacent the cam 146. The surfacecam 148 is vided with a diametrically opposed p nts 149-149. The shaft144 is ted to be shifted endwise' so as toposition either'of-the cams146,01 148 into enment with the tension rod 133. In or- Y to retain theshaft144 in either of its previously mentioned set positions, I haveprovided a hook-shaped latch 150 which is pivoted at 151 to the head 8,the latch bein adapted to enga e in either of the periphera grooves ,152an 153 formed in the shaft 144. The grooves 152 and. 153 are spacedapart a .distanceequal to the distance between the centers of the cams146 and 148.

I in the groove 152, the cam 146 will be As a resu'lt,'when the latch150 is positioned cated in 000 rative relation to the tension 'rod-133,111 when the latch 150 engages in the groove 153, the. cam-148' willbe located coo rative position to the tension rod e worm 1 whichv isfixed to the shaft 144 isof a length suflicient to permit of thisendwise adjustment of the r0d 144 with tttt ttt' out disconnecting saidworm fromits driving'connection. Therefore, when the cam 148 ispositioned to cooperate-with the ten-- sion rod 133, the diametricallyhigh points! 149149 will automatically release the ten"- theseam will beformed of stitches which are each set loosely.-

In the operatlon of the machine,the fabric is positioned in propersewing relation,

relative to thepresser foot as illustrated in Figures land 13,the edgeport-ion of'the super-imposed layer 92 belng guided within treme edgeportion which is covered by the binding 93 being held above the plungerand out of. engagement therewith by means of the shelf 109 of thePresser-foot. -The mart ginal edge portion of the binding 93 is slightlyelevated by the lifting device107 which is attached to the Presser-foot.This the channel 1020f the resser-foot, the ex]- lifting device servesto lift the marginaledge portion of said binding so as to permit theneedle point to enter thereunder and close to the line of thethrough-and-throug'h stitches 94. Inasmuch as the superimposed layer issupported above the path of the needle\ reciprocation by means of theshelf 109, the needle will always netrate said superim' osed layer. Itis desirable to have the nee e alternately penetrate the basev layer 91and this is accomplishedb'y means of the plunger 51 which causes saidbase layer to be alternately crimped for penemo tration by theneedleduring alternate reciprocations thereof. This alternate crimping orbendi about by't e following:', When-.eitherof he cradle 63 will plungerrock shaft 60. The highest-position i h points 73 of the cam 72 is enged by the roller 77, the

rocked thus elevating the of the base layer 91 is brought of the plungerrock shaft 60 through the medium of t e high'points 73 above noted,

determines theposition of the base layer relative to the path of needletravel. Therefore, this determines the depth of needle] enetration inthe base layer.

of movement for adjustment of the bodily position of reciprocation ofthe plunger,-

thus providing a plunger mechanism which will take care of fabrics ofdifferent weights. high point of the cam and approaches the low point 74thereof the cradle 63 will be returned, that is, rocked, thro h caniwilltend to move upwar y and maintain its contact relation witl1' the roller'77. This upward movement of the cam due I The cam 2 1s cutso as toproduce an extreme limit As the cam roller 77 leaves the "the action ofvthe coil springl'82and t e '12.";

to the rocking movement of the cradle 63' necessarily lowers the plungerrock shaft 60 and censequently the lowest verticalosition ofreciprocation of the plunger is o tained.

1b sion during the setting of all stitches. Thus '1 i to the length ofone stitch base layer by reason of the high point '7 3 only This'extremelow position, however, may be easily regulated through the medium of therod 87 and the sleeve 85 which engage with the rock arm 83 of the cradleand thereby of reciprocation of the needle. Thus when each high point 73ofthe cam engages the cam roller 77 thebase layer 91 is upwardly crimpedandpositioned in the path ofreciprocation of the needle, the needle thuspenetrating not only the superimposed layer.

' ut also entering and emerging from the same face of the base layer.This stitch is loosely set due to the action of the intermittent tensionreleasing mechanism. The fabric is then fed rearwardly a distance equaland the needle in its next movement penetrates only the superimposedlayer 92, the needle escaping the cam leaving the cam roller, and therocking movement of the cradle 63 bein .limited by the proper adjustmentof the rod 8 Thus the plunger is elevated during every other cycle, thatis, during the formation of every other stitch. The parts are so timedthat when the needle thread of the stitch which penetrates thesuperimposed layer 92 only \IS 'beingcast from the hook, the cam147 ofthe tension release is ineffective and consescope of my invention.

quently the'stitch-is tightly set. 1

It is of course to be understood that the details of structure andarrangement of parts may be variously changed and modified withoutdeparting from the spirit and I claim: 1. In a sewing machine, the-combination with a reciprocatory threaded 'needle and a complementalstitch forming mechanism for forming a series of connected stitches,-said 3 mechanism including a rotary hook and a.

' hook, a tension device for the needle thread,"

threaded bobbin, of means for rotating said and means respectivelyreleasing and restor ing said tension device automatically during theformation of alternate stitches whereby said connected stitcheswill bealternately set loose and tight.

2. In a sewing machine, the combinationwith a reciprocatory-threadedneedle and a complemental stitch forming mechanism, for forming a seriesof connected stitches, ofa tension device for the needle thread, including relatively weak and strong pressure springs, the strong pressurespring normally the i 3 of serving to tension the needle' thread, and

means for respectively releasing and restoring said strong pressurespring during the formationofalternate stitches whereb said connectedstitches will be alternate y set loose andtight.

3. In a blind stitch sewing machine, the I combination with areciprocatory threaded needle operating in a constant path and acomplemental stitch forming mechanism for forming a series of connectedstitches, of.-

a" work resenting mechanism operating below sa1 stitch formingmechanism, a vertically'movable plunger operating below the a workmaterial, means for moving the plunger upwardly to bend the material inad,- vance of and for alternate needle penetrations, a tension devicefor the needle thread,

tension device in timed relation only to said alternate needlepenetrations.

1. In a blind stitch sewing machine, the

.and means for automatically releasing said,

combination with a reciprocatory threaded needle operating in a constantpath and a complemental stitch forming mechanism for forming a series ofconnected stitches, of a work presenting mechanism operating below saidstitch forming mechanism, a constantly reciprocatory plunger operatingbelow the material, means for bodily elevating the plunger withoutdisturbi g its reciprocatory movements to bend the material inadvance ofand for alternate needle penetrations, a tension device for the needlethread, and means for automatically releasing said tenternate needlepenetrations.

5. In a sewing machine, the combination with a frame having a bore, of arod mounted inv said bore for trelative longitudinal movements andprovided with a shoulder, of

.sion device in timed relation only to said ala pair of tension discsmounted on the rodbetween the shoulder and the frame, interposed betweenthe frame and the rod for yieldingly clamping said discs between forintermittently moving said rod against the tension of said spring torelease saidpredetermined adjustable means for in discs, intermittentlymoving said. rod againstthe tension of said spring comprising a lonitudinally adjustable cam-shaft, a plurality of differently timed camscarried thereby and respectivel adapted for engagement with the end 0said rod in difieren't positions of adjustment of said cam-shaft, andmeans'for retaining said shaft in an adjusted position.

6. In a sewing" machine, the combination with a frame having a bore, ofa rod mounted in said bore for relative longitudinal movements andprovided with a shoulder,

of a pairof tension discs mounted on the.

rod between the shoulder and the frame, a spring interposed a spring theframe and the shoulder of the rod, means between the frame and the "9rod for yieldingly clamping said discs between the frame andthe'shoulder of the rod, means for intermittently moving said rodagainst the tension of said ring to release said discs, predetermined ajustable means I for intermittently moving said rod against 'the tensionof said spring, com using a longitudinally adjustab e cam-sha apluraht'y of differently timed cams carried thereby and respectivelyadapted for engagement with the end of said rod in different positionsof adjustment of said cam-shaft,

said shaft being formed with spaced annu- -lar. recesses, and means forretaining said shaft in an adjustedposition comprising a keeper pivotedon the frameand engageable in a registering recess. P

7. In a blind stitch combination with a reclprocatory threaded needleoperating in a. constant path and a complemental stitch formingmechanism for forming aseries of connected stltches, of a workpresenting mechanism including a presser foot havinimeans for supportingthe fell above the ase layer,-, whereby the needle will penetrate saidfell during each reciprocation, means for elevating the base layer intothe path and in advance of only alternate needle reciprocations wherebysaid needle will alternately penetrate the. fell and'thefclland baselayer, a tension device for the needle thread, and means for auto--matically releasing said tension device duringthe formation of eachstitch penetrating fell, and an edge lifting device secured to the bodyfportion for, raising the m rginal portion 0 the-binding for permittingthe needle to pass through the fell directly under the raised portion ofthe binding, a feeding mechanism cooperating with the foot to" feed thematerial past said stitch forming mechanism, a vertically movable pluner operating below the presser foot, means or moving the plunger upwardlto bend the body fabric in advance of an for predeter mined needlepenetrations whereby the needle during one reciprocation will enter thefell only and during another reciprocation will enter both the fell andthe body fabric,1a tension device for the needle thread, I and means"for releasing and restoring said tension device automatically during theformation of the stitches whereby redetermined connected stitches willtight respectively.

felling machine, the

be set oose and 9. In a blind stitch sewing mama 01% am a o o I l j ingseams, the combination with a reclprocatory threaded needle-and acomplemental' stitch forming mechanism for forming a series of connectedstitches, of a presser foot disposed below said needle and comprising abody portion having a rearwardly extending slot for guiding a previouslybound fell, and an edge lifting portion for ralsing the marginal portionof the binding for permitting the needle to pass j through the felldirectly under the raised a,

portion ofthe binding, a feeding mechanism cooperating with the foot tofeed the material past said stitch forming mechanism, a verticallymovable plunger operating below the presser foot, means for moving theplunger upwardly to bend the body fabric device secured'to the body i inadvance of and for predetermined needle penetrations whereby the needleduring one reciprocation will enter the fell only and duringlanotherreciprocation will enter both and the body fabric, a tension dethe felvice for the needle thread, and means for"- automatically releasing saidtension during the formation of the stitches-connecting the fell and thebody fabric and for automatically restoring the tension. during theformatioln of the stitches passing through the fell on y. r

10. In a blindstitch sewing machine for felling seams, the combinationwitha reciprocatory threaded needle and a comple mental stitch formingmechanism for forming a series of connectedstitches, of a resser footdisposed below said needle an comprising a body portion having arearwardly extending slot for giiiding a previously bound fell, and anedge lifting device secured to the body portion for raising the marginalportion of the 'binding for; permittmg the needle to passthrough thefell directly under the raised portion of the binding, a feedingmechanism cooperating with the foot to feed the material past saidstitch forming mechanism, a vertically movable means for moving theplunger upwardly to bend the body fabric in advance of and for alternateneedle penetrations" whereby the tion will enter both ,thefell and thebod plunger operating below the" presser foot,

fabric, a tension device for. the needle threa a and means forrespectively releasing and restoring said tension device automaticallyduring the formation of alternate stitches whereb said connectedstitches will be'alternate y set loose and tight.

ing a body portion having'a rearwardly ex- L 11. In a blind stitchsewing machinefor felling seams, the combination with a retending slotfor guiding a previously bound ,fell, and an edge lifting device securedto the body portion for raising the marginal portion of the binding forpermittingthe needle to pass through the fell directly under the raisedportion of the binding, a feeding mechanism cooperating with the foot tofeed the material past said stitch forming mocha:

' nism, a vertically movable plunger operating below the presser foot,means for moving the plunger upwardly to bend the body fabric in advanceof and for alternate needle penetrations whereby the needle during onereciprocation will enter the fell only and during the next reciprocationwill enter both the fell and the body fabric, a tension device for theneedle thread, and means for automatically releasing said tension duringthe formation of the stitches connecting the fell and the body fabricand for automatically re: storing the tension during the formation ofthe stitches passing through the fell only.

In testimony whereof I hereunto aflix my signature.

CHARLES W. MUELLER.

